Pro-Russia separatists claimed Saturday that they had trapped thousands of Ukrainian government troops in the course of fierce fighting in Ukraine's troubled east.

“We have practically encircled 8,000 to 10,000 Kiev junta troops in the area around” the town of Debaltseve, Eduard Basurin, chief political officer of the self-proclaimed Donetsk People's Republic armed forces, said by phone. “The only road connecting them with the other troops is under our close artillery fire day and night and they can survive only if they raise a white flag and surrender.”

Ukrainian troops had refused to surrender, the separatist senior commander said, “so we will have to destroy all of them.”

Basurin said both sides had sustained heavy casualties in the last thee days of fighting around Debaltseve but refused to provide a specific toll. Ukrainian Defense Minister Stepan Poltorak said that 15 Ukrainian servicemen had been killed in the fighting and 30 wounded.

Twelve civilians were also killed by the artillery fire near Debaltseve, Donetsk region Police Chief Vyacheslav Abroskin told the UNIAN news agency. At least 310 residents were evacuated from the scene of the fighting Saturday, and about 1,000 had already been evacuated, UNIAN reported.

Ukraine fighting

Sergei L. Loiko / Los Angeles times

A Ukrainian soldier, with a destroyed separatist convoy in the background, near Donetsk airport on Jan. 23.

“We are firmly holding our defense positions along the entire front lines from Donetsk to Mariupol, and none of our contingents or groups have yet been encircled,” Gen.-Maj. Alexander Rozmaznin said. “The enemy controls half of [the town of] Uglegorsk, where we are engaged in heavy street fighting, but there is no chance they can enter Debaltseve.”

The general said the pro-Russia separatists were heavily armed and supported by Russian T-72 and T-80 tanks, along with sophisticated Russian artillery systems. He also said that hundreds of Russian soldiers were fighting alongside the separatists.

“We fully understand that today we are mostly fighting against Russian regular troops and their quite professional artillery and tank crews,” Rozmaznin said. “We know that they are maneuvering to entrap our forces, but we are prepared for it and they are already feeling our powerful response and retreating, sustaining heavy casualties.”

A T-72 tank crew was captured Saturday and was being interrogated, Poltorak said.

Russia has repeatedly refused to acknowledge that it is providing military assistance and troops to the separatists and has insisted that Ukrainian separatists used T-64 tanks they had captured from Ukrainian military. Ukraine’s army doesn't have T-72 or T-80 tanks.

The shaky truce agreed upon in Minsk, Belarus, in September had been violated many times and discarded by both sides in recent days as heavy fighting broke out, including at the Donetsk airport, where the Ukrainian army lost several key buildings.

“In the course of the last 24 hours the situation has rapidly deteriorated in eastern Ukraine affecting innocent civilians,” the Organization for Security and Cooperation in Europe said Saturday on its website. “Lives have been lost and many have been injured.”

OSCE Chairperson-in-Office Ivica Dacic expressed profound regret for the loss of lives and called upon all sides to refrain from violence and indiscriminate use of weapons, the statement said.

The United Nations said recently that the conflict in eastern Ukraine, which began in 2014, had claimed more than 5,000 lives.

Special correspondent Butenko reported from Kiev and Times staff writer Loiko from Moscow.